Hello all,
I have an 89 XJ with 4.0, I am pulling my transmission out due to a bad leak coming out from bell housing where the torque converter sits (all fluid drained out in about 15 min). While pulling the tranny is there any other maintenance or upgrades you recommend while I have the tranny out? Currently I am on Dana 44’s, Detroit lockers front and rear, rubicon 5.5” short arm lift, np231 transfer case, aw4 automatic transmission with slip yoke eliminator kit.

One thing that comes to mind is maybe replace rear main seal, I heard these are common leak point? I have about 150k miles. Is there a good upgrade for the np231 transfer case while it is out? One other item I am thinking is upgrade the inter cooler connection points as the quick disconnects have failed already and had to replace due to leak, also thinking of adding a transmission temp gauge. I would like to maximize the opportunity while I have the transmission out.

Also any info you can point me to regarding where the possible leak points are at with current situation would be helpful, based on research I’ve done the input shaft seal on transmission may be leaking, I’ve also read transmission pump bushing as well? Definitely not a transmission guy so any help is greatly appreciated. The unit is leaking out of the weep hole at the bell housing and service plate (where torque converter is located behind flex plate).

thank you all for any good advice!

 

Definitely rear main.
231 4:1 kit this should fix all your tcase leaks.

Aw4 transgo shift kit. I wish there were billett tourqe converters for the aw4

 

Cool, thanks much for the info, do you know who makes the 4:1 kit for the tcase?

 

I guess the 4:1 is no longer available

 

They stopped offering the kit a few years ago though you can see it still on websites. I was told their case was cracking which is why they discontinued it.

 

As stated above they had trouble with the product. It also had lubrication problems and would burn up if the rig was driven at highway speeds. So they said you shouldn't drive over 35mph if you had it installed, even in 2WD.

 

based on that, will not be pursing 4:1.

so far got the pump seal and bushing changed out, input shaft seal and took the converter down to shop for pressure test/inspection.

next on the agenda is rear main seal replacement...

thanks for info